Difference: GMProjectProgress (5 vs. 6)

Revision 62013-05-23 - DanProtopopescu

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LC Project Progress

Project Overview
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Project Aim

The main aim is to study the properties of the Higgs particle and W W fusion in electron-positron collisions at a linear collider. The project will focus on the direct reconstruction of the H → b bbar decay mode, as this has the highest branching ratio for a Higgs of mass around 120 GeV as discovered at CERN.

Project Interim Report

Final Report

Invariant Mass of Higgs (MC simulated events)

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Determined the invariant mass of the reconstructed Higgs boson in the MC simulated events from its two b jets, and its two c jets (from the decay mode of H → c cbar). Suitable Gaussian fits were applied to the invariant mass distributions to find the peak for these decay modes, with suitable errors quantified.

Attached plots:

H → b bbar with Gaussian fit

H → c cbar with Gaussian fit

Project Plan

The aim is to now implement a neural network flavour tagging processor to separate background and signal events, and to find how well the reconstructed particles compare with the “true” underlying particles. I will move on to look at the WW fusion process at a higher centre-of-mass energy and aim to construct a full Higgs cross-section analysis.


  • Reconstruct H->bb using truth tagging in ZH
  • Implement "real" b-tagging and do the same
  • Switch to WW fusion and find the H->bb peak there
  • Make a WW->H->bb cross-section measurement

Useful Links

META FILEATTACHMENT attachment="b_jet_mass50000.ps" attr="" comment="b jet mass from 50000 events" date="1359744043" name="b_jet_mass50000.ps" path="b_jet_mass50000.ps" size="9954" stream="b_jet_mass50000.ps" tmpFilename="/usr/tmp/CGItemp22635" user="GavinMurdoch" version="1"
META FILEATTACHMENT attachment="c_jet_mass50000.ps" attr="" comment="c jet mass from 50000 events" date="1359744056" name="c_jet_mass50000.ps" path="c_jet_mass50000.ps" size="9218" stream="c_jet_mass50000.ps" tmpFilename="/usr/tmp/CGItemp22600" user="GavinMurdoch" version="1"
META FILEATTACHMENT attachment="plot_gaus_limits_100_147.png" attr="" comment="Invariant Mass of Higgs (H->bb)" date="1360756154" name="plot_gaus_limits_100_147.png" path="plot_gaus_limits_100_147.png" size="24038" stream="plot_gaus_limits_100_147.png" tmpFilename="/usr/tmp/CGItemp29290" user="GavinMurdoch" version="1"
META FILEATTACHMENT attachment="cplot_gaus_limits_105_154.png" attr="" comment="Invariant Mass of Higgs (H->cc)" date="1360756217" name="cplot_gaus_limits_105_154.png" path="cplot_gaus_limits_105_154.png" size="20400" stream="cplot_gaus_limits_105_154.png" tmpFilename="/usr/tmp/CGItemp29258" user="GavinMurdoch" version="1"
META FILEATTACHMENT attachment="Murdoch_Gavin_0900886_InterimReport.pdf" attr="" comment="Higgs Properties Interim Report" date="1360757170" name="Murdoch_Gavin_0900886_InterimReport.pdf" path="Murdoch_Gavin_0900886_InterimReport.pdf" size="88483" stream="Murdoch_Gavin_0900886_InterimReport.pdf" tmpFilename="/usr/tmp/CGItemp29110" user="GavinMurdoch" version="1"
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